Structure for adjustably attaching a disc brake caliper to a bicycle frame

ABSTRACT

An attachment structure for a caliper of a disc brake assembly consisting of a caliper and a rotor. The caliper is attached to a wheel supporting portion of a cycle frame which supports a wheel with the rotor fixedly attached to the wheel and the rotor lying in a fixed plane relative to the supporting portion of the frame. The supporting portion of the frame has a pair of attachment bores oriented to attach the caliper with the rotor received between a pair of brake pads advanced into and out of contact with the rotor by the caliper along a select axis. The attachment structure allows for infinite variation of the angle of incidence between the select axis and the plane of the rotor within a defined range. Attachment bolts secure the caliper to the frame with a select angle of incidence between the select axis and the plane of the rotor.

RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication Ser. No. 60/142,559, filed Jul. 7, 1999, entitled “Structurefor Adjustably Attaching a Disc Brake Caliper to a Bicycle Frame.”

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention is directed toward bicycle brakes, and moreparticularly toward a structure for adjustably attaching a disc brakecaliper to a bicycle frame.

2. Background Art

Disc brakes for bicycles are growing in popularity as consumers demandand bicycle manufacturers strive to provide ever advancing technology onbicycles. Disc brake systems generally consist of a rotor which isfixedly attached to the hub of a bicycle wheel and a caliper which isfixedly attached to a wheel supporting portion of the bicycle frame andwhich receives the rotor between a pair of bike pads which are advancedinto and out of contact with the rotor along a select axis. The wheelsupporting portion of the frame has some structure for attaching thecaliper to the chain or seat stay in the rear or fork in the front ofthe frame. This structure typically consists of a boss or a pair ofbosses which extend from the frame substantially parallel to the planeof the rotor and which have internally threaded bores in their distalends which are intended to lie in a plane normal to the plane of therotor. The caliper, in turn, has a mounting foot which extends from thecaliper body and includes a pair of holes corresponding to the bores inthe ends of the attachment bosses. The caliper is then bolted to theframe by bolts axially received the holes in the mounting foot. Whenproperly aligned, the rotor will be received between the brake pads ofthe caliper so that the brake pads of the caliper are advanced into andout of contact with the rotor along an axis that is normal to the planeof the rotor.

Assuming that the attachment bosses extend parallel to the plane of therotor and that the ends of the attachment bosses lie in a planeperpendicular to the plane of the rotor, prior art calipers would beproperly aligned with the brake pads being advanced along an axis normalto the rotor. In practice, however, the normal range of manufacturingtolerances in the bicycle and caliper makes it unlikely that the caliperwill be properly aligned with respect to the rotor. When the caliper isnot properly aligned, the brake pads will not strike the rotor flushwhich can degrade brake performance. It can even lead to the brake padsrubbing against the rotor and deteriorating bicycle performance.

One structure known in the prior art for addressing this improperalignment is providing elongate slots on the mounting foot of thecaliper corresponding to the bores in the mounting bosses which extendsubstantially parallel to the select axis of advancement of the pads.These slots allow translational movement of the caliper toward and awayfrom the rotor to precisely position the rotor intermediate the pads ofthe caliper. In addition, these slots enable the caliper to be cantedabout an axis parallel to an axis of the mounting boss bores tocompensate for some misalignment between the rotor and the caliper.However, because these slots only allow for translational movement andsome range of canting, they do not enable proper alignment with therotor if the tolerances cause misalignment outside of these limiteddirections of travel.

The present invention is directed toward overcoming one or more of theproblems discussed above.

BRIEF SUMMARY OF THE INVENTION

The present invention is an attachment structure for a caliper of a discbrake assembly consisting of a caliper and a rotor. The caliper isattached to a wheel supporting portion of a cycle frame which supports awheel with the rotor fixedly attached to the wheel and the rotor lyingin a fixed plane relative to the supporting portion of the frame. Thesupporting portion of the frame has a pair of attachment bores orientedto attach the caliper with the rotor received between a pair of brakepads advanced into and out of contact with the rotor by the caliperalong a select axis. The attachment structure allows for infinitevariation of the angle of incidence between the select axis and theplane of the rotor within a defined range. Attachment bolts secure thecaliper to the frame with a select angle of incidence between the selectaxis and the plane of the rotor.

Another aspect of the present invention is a disc brake assemblyattachable to a wheel supporting portion of a frame of a cycle. The discbrake assembly includes a rotor fixedly attached to a wheel mounted tothe wheel supporting portion of the frame, with the rotor residing in aplane of fixed orientation relative to the wheel supporting portion ofthe frame. A caliper receives the rotor between a pair of brake padswith the caliper advancing the brake pads into and out of contact withthe rotor along a select axis. An attachment structure attaches thecaliper to the wheel supporting portion of the frame with the angle ofincidence between the select axis and the plane of rotor beinginfinitely variable within a defined range. In this manner, the calipercan be aligned with the select axis normal to the rotor. At least onebolt is operatively associated with the attaching structure to securethe caliper to the frame with the select axis aligned normal to therotor. The attaching structure preferably includes slots on the calipersubstantially parallel to the select axis for enabling translationalmovement of the caliper toward and away from the rotor.

The attaching structure may include a pair of spaced bores on the wheelsupporting portion of the frame defining a line substantially parallelto the plane of the rotor, the bores having openings which lie in aplane substantially normal to the plane of the rotor. A convex surfaceis associated with the mouth of each bore. A mating concave surface isassociated with a bottom of a mounting foot of the caliper. Alignedholes extend through each of the concave and convex surfaces andcorrespond to the bores in the wheel supporting portion of the frame. Apair of slots in the mounting foot of the caliper also corresponds tothe bores. These slots are substantially parallel to the select axis. Abolt having a head and a shaft is axially received in each slot, alignedhole and corresponding bore with the head protruding therefrom. The boltis threadably engaged with the bores to maintain the caliper with theselect axis aligned normal to the rotor. The attaching structurepreferably further includes a pair of washers having mating concave andconvex surfaces and opposite flat surfaces receiving the bolt with oneof the flat surfaces abutting a top of the mounting foot of the caliperand the other of the flat surfaces abutting the head of the bolt.

In one embodiment, the mating concave and convex surfaces associatedwith the mouth of each bore and the underside of the mounting foot ofthe caliper comprise a pair of washers having mating concave and convexsurfaces and opposite flat surfaces, with the washer pairs residing withone of the flat surfaces abutting the bottom of the caliper mountingfoot and the other of the flat surfaces abutting the wheel supportingportion of the frame.

In another embodiment, the mating concave and convex surfaces associatedwith the mouth of each bore and the bottom of the mounting foot consistsof a pair of plates having the mating concave and convex surfaces andopposite flat surfaces, the pair of plates further including the alignedholes, the plates residing with one flat surface abutting the bottom ofthe mounting foot and the other flat surface abutting the wheelsupporting portion of the frame. Preferably, the aligned holes areelongate and correspond to the slots in the caliper mounting foot.

Yet another aspect of the present invention is a structure for attachinga caliper of a disc brake system to a cycle frame with a pair of brakepads advanced by the caliper in operative engagement with a rotor of thedisc brake system, the frame having a pair of threaded caliper mountingbores and the caliper having a mounting foot. The attachment structureconsists of mating concave and convex surfaces between the frame and abottom of the caliper mounting foot to pivot the caliper about apivoting axis. A pair of holes corresponding to the caliper mountingbores extend through the concave and convex mounting surfaces. A pair ofspaced slots on the caliper mounting foot extend transverse the pivotingaxis and are aligned with the holes and the mounting bores. A pair ofbolts are axially received in the aligned slots, holes and the threadedmounting bores with the bolts engaging the threaded mounting bores tomaintain the pads of the caliper in a select orientation relative to therotor. The mating concave and convex surfaces may be a pair of washersresiding between the bottom of the caliper mounting foot and the framecorresponding to each of the caliper mounting bores. Alternatively, themating concave and convex surfaces residing between the bottom of thecaliper mounting foot and the frame may be formed on a pair of elongateplates. Alternatively, one of the concave and convex surfaces may be onthe bottom of the caliper mounting foot and the other may be on anelongate plate residing between the bottom of the caliper mounting footand the frame. In this embodiment, the pair of holes in the elongateplate are preferably elongate to correspond to the slots in the calipermounting foot. Preferably, mating concave and convex surfaces arefurther provided between the head of the bolt and the top of the calipermounting foot. The mating concave and convex surfaces are preferably ona pair of washers corresponding to each of the bolt heads residingbetween the bolt heads and the top of the caliper mounting foot.

The structure for adjustably attaching a disc brake caliper to a bicycleframe of the present invention allows for infinite variation of theangle of incidence between an axis of movement of caliper brake pads andthe plane of a rotor within a defined range. Thus, the caliper can beadjusted so that the select axis in is the desired orientation of normalto the plane of the rotor notwithstanding manufacturing tolerances andmanufacturing defects that would cause the axis of pad travel of priorart calipers not to be normal to the plane of the rotor. In addition,the attachment structure allows translation of the caliper toward andaway from the rotor to compensate for variations in the spacing betweenthe attachment studs and the disc brake rotor amongst the bicycles ofvarious manufacturers. The structure for adjustably attaching the discbrake is virtually self-adjusting within its defined range. The calipercan be readily self-aligned simply by loosening the attachment bolts,actuating the brake pads into abutment with the rotor and thentightening the attachment bolts. Thus, the many advantages of having theselect axis of movement of the brake pads normal to the rotor can beachieved with minimal effort on the part of the user. Moreover, thestructure providing these many advantages is inexpensive to manufactureand can be made from off the shelf parts making it an inexpensivesolution to an otherwise vexing problem.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a caliper mounted to the front fork of abicycle in operative association with a rotor using a structure foradjustably attaching a disc brake to a bicycle frame of the presentinvention;

FIG. 2 is an exploded view of the structure for adjustably attaching adisc brake caliper to a front fork of a bicycle frame of FIG. 1;

FIG. 3 is a perspective view of a caliper mounted to a chain stay of abicycle frame in operative engagement with a rotor using a secondembodiment of a structure for adjustably attaching a disc brake to abicycle frame of the present invention;

FIG. 4 is an exploded view the structure for adjustably attaching a discbrake caliper to bicycle frame of FIG. 3;

FIG. 5 is a rear view of the caliper of FIG. 1 showing the translationalmovement of the caliper relative to the rotor afforded by the presentinvention;

FIG. 6 is a rear view of the caliper of FIG. 1 showing the cantingmovement afforded by the caliper relative to a rotor of the presentinvention;

FIG. 7 is a bottom view of the caliper of FIG. 1 showing the hingedmovement of the caliper relative to the rotor afforded by the presentinvention; and

FIG. 8 is a perspective view of a third embodiment of an attachmentstructure of the present invention providing the translational movementof FIG. 5, the canting movement of FIG. 6, the hinged movement of FIG. 7as well as axial movement along a rod.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A disc brake system 10 consisting of a caliper 12 and a rotor 14 isillustrated in FIG. 1 with the caliper attached to a front fork 16 of abicycle frame. Although omitted for the sake of clarity, the rotor 14 isfixedly attached to a hub of a wheel for rotation with the wheel withthe wheel hub being attached to the bracket 18 of the front fork. Thus,the front fork 16 acts as a wheel support portion of the bicycle frame.The rotor 14 is maintained in a fixed plane relative to the wheel andthe front fork.

The rotor 14 is received between a pair of brake pads 20, 22 attached tothe caliper 12 which are best viewed in FIG. 7. The brake pads areadvanced into and out of contact with the rotor along a select axis 24which is intended to be normal to the plane 26 of the rotor 14.

A pair of attachment bosses 30 extend from the fork 16 preferablyparallel to the plane of the rotor 14. Referring to FIG. 2, the distalends 32 of the attachment bosses have an internally threaded bore 34which is also preferably parallel to the plane of the rotor 14. Thedistal ends of the attachment bosses 30 preferably each lie in a commonplane which is normal to the plane of the rotor 14. However, due tomanufacturing tolerances and in some cases manufacturing defects, oftenone of the axes of the threaded bores 34, the distal ends 32 of theattachment bosses 30 or the plane of the rotor 14 are not precisely inthe desired alignment. A structure for adjustably attaching the caliperto a bicycle frame 28 is intended to allow for necessary realignment.

The structure for adjustably attaching the caliper to a bicycle frame 28consists of first and second pairs of washers 36, 38. A first washer 40of the washer pair 36 has a concave semispherical surface 42 and a flatsurface 44 with a hole 45 extending there between. The second washer 46of the washer pair 36 has a convex semispherical surface 48 which mateswith the concave surface 42. Opposite the convex surface 48 is a flatsurface 50. A hole 51 extends between the surfaces. The second washerpair 38 is identical to the first washer pair 36. The first and secondwasher pairs 36, 38 reside between the distal ends 32 of the attachmentbosses 30 and the bottom 52 of a mounting foot 54 of the caliper 12.Third and fourth identical washer pairs 56, 58 reside between a topsurface 60 of the mounting foot 54 and the head 62 of bolt 64. Themounting foot 54 has a pair of elongate slots 66 which extend lengthwiseparallel to the select axis 24. The shaft 68 of the bolt 64 is axiallyreceived through the holes in the third washer pair and the elongateslot 66 and the holes in the first washer pair 36 and the shaft 68 isthreadably engaged with the bore 34 of the attachment boss 30. Aconventional washer 70 may be further provided adjacent the head 62 ofthe attachment bolt 64.

In use, with the caliper attached as described above, the caliper ismoveable in several directions which enable the angle of incidence ofthe select axis 24 to vary infinitely within a select range so that theselect axis 24 can be aligned normal to the plane of the rotor 14.Referring to FIG. 1, arrow 72 illustrates how the caliper can be movedby translation toward and away from the rotor 14. This movement is alsoillustrated by the arrows 72 in FIG. 5. This movement is possible byvirtue of the elongate slots 66. The elongate slots 66 also enablecanting of the caliper 12 relative to the rotor 14 as illustrated byarcuate arrow 74 in FIG. 1 and also in FIG. 6. Finally, the caliper canbe pivoted about a virtual axis 76 such that the caliper is in essencehinged about the engaging concave and convex surfaces of the first andsecond washer pairs 36, 38. This movement is illustrated by the arrow 78in FIGS. 1 and 7.

By virtue of the canting movement allowed by the elongate slots 66 andthe hinged movement allowed by the engaging concave and convex surfaceof the first and second washer pairs 36,38, the select axis 24 can bemoved relative to the plane of the rotor 14 to have an angle ofincidence which is infinitely variable in three dimensions within aselect range of movement. Thus, the caliper 12 can be aligned so thatthe select axis 24 is normal to the plane of the rotor 14. Furthermore,the elongate slot 66 enables translational movement of the caliperrelative to the rotor 14 to allow the rotor 14 to be placed in a desiredposition between the brake pads 22.

FIG. 3 illustrates a second embodiment of the structure for adjustablyattaching the caliper to a bicycle frame 28A. As best seen in FIG. 4,this embodiment, a mounting bracket 86 is fixedly attached to a chainstay 88 which would be at the rear of the bicycle frame. A bracket 90 isat the intersection of the chain stay 88 and the seat stay 92 to which awheel, which has been omitted for clarity, can be attached to the rearof the bicycle frame. The rotor 14A is fixedly attached to a hub of thewheel. As with rotor 14 of FIG. 1, rotor 14A is maintained in a fixedplane relative to the wheel and the chain stay 88. The mounting bracket86 has a pair of internally threaded bores 93 the openings of which liein a plane defined by the surface 94 which is intended to besubstantially perpendicular to the plane of the rotor 14A.

The second embodiment of the attachment structure for adjustablyattaching a caliper to a bicycle frame 28A consists of an elongate plate95 having a pair of transverse elongate slots 96 extending between aconcave surface 98 and a flat surface 100. The caliper 12A has amounting foot 50A having an elongate convex bottom surface 102 whichmates with the concave surface 98 of the elongate plate 95. A pair ofelongate slots 104 corresponding with and aligning with the elongateslots 96 in the elongate plate 95 extend parallel to the select axis 24between the top 106 and the convex bottom 102 of the foot 50A. First andsecond washer pairs 108, 110 which are identical to the washer pair 36discussed above with regard to FIG. 2, reside between the head 62A ofthe attachment bolt 64A and the top 106 of the mounting foot 50A. Theshafts 68A are axially received by an optional conventional washer 111and the washer pairs 108,110, the elongate slots 104, in the mountingfoot 50A and the elongate slots 96 in the elongate plate 94 andthreadably engaged in the threaded bores 93 to maintain the caliper in aselect position.

As with the first embodiment discussed with reference to FIGS. 1, 2, 5 ,6 and 7, the second embodiment in FIG. 3 has elongate slots 96, 104allow translational movement in the direction of the arrow 72 andcanting movement in the direction of the arcuate arrow 74. The matingconcave and convex surfaces allow for hinged movement as illustrated byarrow 78. In this manner, the second embodiment 28A allows for the samemovement and adjustable attachment as the first embodiment 28.

It should be noted that the first and second washer pairs 36, 38 couldbe substituted for the plate 94 and the convex surface 102 of the foot50A. However, the second embodiment provides a greater surface area toresist slipping.

FIG. 8 illustrates a third embodiment in the present invention thatallows for a fourth direction of movement of the caliper 12. In thisembodiment, a caliper attachment bracket 120 consists of a rod 122attached to footing plates 124 at each end. The footing plates 124include elongate slots 126. The footing plates 124 are attachable to thedistal ends of the attachment bosses 30 discussed with reference toFIGS. 1 and 2. A plate 128 having a transverse chanel 130 therein forreceiving the bar 122 has a number of holes 132 to allow for fixedattachment of the plate 128 to the bottom of the caliper 12 with anumber of screws or bolts, not shown. Once attached, the caliper can bemoved translationally as indicated by the arrow 72 canted relative to arotor illustrated by the arcuate arrows 74 in a hinged manner asillustrated by the arcuate arrow 78 and axially of the bar 122 asillustrated by the arrow 134. Thus, the third embodiment illustrated inFIG. 8 allows for an additional direction of travel over the first andsecond embodiments 28, 28A.

The caliper attachment structure of the present invention allows for agreat range of movement of the caliper so that the caliper pads cantravel along a select axis normal to the plane of the operativelyassociated rotor regardless of manufacturing tolerances and minordefects. In this manner, braking efficiency can be maximized by assuringthat the brake pads are brought into full-flush contact with the rotor.In addition, undesired rubbing between the caliper pads and rotor bymisalignment can be minimized. The caliper attachment structure alsoprovides for virtually instantaneous self-alignment. The user need onlyloosen the attachment bolts, actuate the caliper to advance the brakepads into engagement with the rotor and then tighten the attachmentbolts. The attachment structure therefore compensates for manufacturingtolerances and manufacturing defects which can result in misalignmentbetween caliper pads and a rotor of a disc brake system. As can bereadily appreciated, these many advantages are provided by a structurewhich is capable of being fabricated from off the shelf parts and iseasily assembled and, perhaps most importantly, is extremely easy for auser to employ.

What is claimed is:
 1. A disc brake assembly attachable to a wheelsupporting portion of a frame of a cycle, the disc brake assemblycomprising: a rotor fixedly attached to a wheel mounted to the wheelsupporting portion of the frame, the rotor residing in a plane of fixedorientation relative to the wheel supporting portion of the frame; acaliper receiving the rotor between a pair of brake pads, the caliperadvancing at least one of the brake pads to bring the brake pads intoand out of contact with the rotor along a select axis; means forattaching the caliper to the wheel supporting portion of the frame withthe angle of incidence between the select axis and the plane of therotor being infinitely variable within a defined range, whereby thecaliper can be aligned with the select axis normal to the rotor; and atleast two bolts operatively associated with the attaching means tosecure the caliper to the frame with the select axis aligned normal tothe rotor.
 2. The disc brake assembly of claim 1 wherein the means forattaching comprises slots on the caliper substantially parallel to theselect axis for enabling translational movement of the caliper towardand away from the rotor, the at least two bolts being axially receivedin the slots.
 3. The disc brake assembly of claim 1 wherein the meansfor attaching comprises: a pair of spaced bores on the supportingportion of the frame defining a line substantially parallel to the planeof the rotor, the bores having openings which lie in a planesubstantially normal to the plane of the rotor; one of a concave and aconvex surface associated with the mouth of each bore; a mating one of aconcave and a convex surface associated with a bottom of a foot of thecaliper; aligned holes extending through each of the concave and convexsurfaces corresponding to the bores; a pair of slots in the mountingfoot of the caliper corresponding to the bores, the slots beingsubstantially parallel to the select axis; and each bolt having a headand a shaft with the shaft received in a slot, aligned hole andcorresponding bore with the head protruding therefrom and the bolt beingthreadably engaged with each bore to maintain the caliper with theselect axis aligned normal to the rotor.
 4. The disc brake assembly ofclaim 3 further comprising a pair of washers having mating concave andconvex surfaces and opposite flat surfaces receiving each bolt with oneof the flat surfaces abutting the top of the mounting foot of thecaliper and the other of the flat surfaces abutting the head of eachbolt.
 5. The disc brake assembly of claim 3 wherein mating concave andconvex surfaces associated with the mouth of each bore and the undersideof the mounting foot of the caliper comprise a pair of washers havingthe mating concave and convex surfaces and opposite flat surfaces, thewashers residing with one flat surface abutting the bottom of thecaliper mounting foot and the other flat surface abutting the wheelsupporting portion of the frame.
 6. The brake assembly of claim 3wherein the mating concave and convex surfaces associated with the mouthof each bore and the bottom of the mounting foot comprise a pair ofplates having the mating concave and convex surfaces and opposite flatsurfaces, the pair of plates further including the aligned holes, theplates residing with one flat surface abutting the bottom of themounting foot and the other flat surface abutting the wheel supportingportion of the frame.
 7. The assembly of claim 3 wherein the matingconcave and convex surfaces associated with the mouth of each bore andthe bottom of the mounting foot comprise one of the mating concave andconvex surfaces on the bottom of the mounting foot and the other on anelongate plate residing between the bottom of the mounting foot and theframe, the aligned holes extending through the mounting foot and theplate.
 8. The assembly of claim 7 wherein the aligned holes are elongateand correspond to the slots in the caliper mounting foot.
 9. A structurefor attaching a caliper of a disc brake system to a cycle frame with apair of brake pads advanced by the caliper in operative engagement witha rotor of the disc brake system, the frame having a pair of threadedcaliper mounting bores and the caliper having a mounting foot, theattaching structure comprising: mating concave and convex surfacesbetween the frame and a bottom of the caliper mounting foot to pivot thecaliper about a pivoting axis with a pair of holes corresponding to thecaliper mounting bores extending through the concave and convexsurfaces; a pair of spaced slots on the caliper mounting foot extendingtransverse the pivoting axis and aligned with the holes and the mountingbores; and a pair of bolts axially received in the aligned slots, holesand threaded mounting bores, the bolts engaging the threaded mountingbores to maintain the pads of the caliper in a select orientationrelative to the rotor.
 10. The attaching structure of claim 9 furthercomprising: mating concave and convex surfaces between a head of eachbolt and a top of the caliper mounting foot.
 11. The attaching structureof claim 10 wherein the mating concave and convex surfaces are on a pairof washers corresponding to each of the bolt heads residing between thebolt heads and the top of the caliper mounting foot.
 12. The attachingstructure of claim 9 wherein the mating concave and convex surfaces areon a pair of washers corresponding to each of the caliper mounting boresresiding between the bottom of the caliper mounting foot and the frame.13. The attaching structure of claim 9 where in the mating concave andconvex surfaces are on a pair of elongate plates residing between thebottom of the caliper mounting foot and the frame.
 14. The attachingstructure of claim 13 wherein one of the mating concave and convexsurfaces is on the bottom of the caliper mounting foot and the other ison an elongate plate residing between the bottom of the caliper mountingfoot and the frame.
 15. The attaching structure of claim 14 wherein thepair of holes in the elongate plate are elongate to correspond to theslots in the caliper mounting foot.
 16. An attachment structure for acaliper of a disc brake assembly comprising the caliper and a rotor, thecaliper being attached to a wheel supporting portion of a cycle framesupporting a wheel with the rotor fixedly attached to the wheel and therotor lying in a fixed plane relative to the supporting portion of theframe, the supporting portion of the frame having a pair of attachmentbores oriented to attach the caliper with the rotor received between apair of brake pads advanced into and out of contact with the rotor bythe caliper along a select axis, the attachment structure allowing forinfinite variation of the angle of incidence between the select axis andthe plane of the rotor within a defined range and the attachmentstructure securing the caliper to the frame with a select angle ofincidence between the select axis and the rotor.
 17. An attachmentstructure for attaching a component to two mounts affixed to a bicycleframe to provide gimbaled movement of the component relative to theframe, the attachment structure comprising: a. mating concave and convexsurfaces between the mounts and a bottom of the component for enablinghinged movement of the component relative to the mounts about a firstaxis with a hole extending between each of the mounts and the componentthrough the concave and convex surfaces; b. a pair of spaced elongateslots on at least one of the component and the mounts extendingtransverse the first axis and each slot aligned with one of the holesthrough the concave and convex surfaces, the spaced slots beingpositioned relative to one another to enable pivoting of the componentrelative to the mounts about a second axis perpendicular to the firstaxis while the slots remain aligned with the holes through the concaveand convex surfaces; and c. a pair of compression members each having ashaft extending through one of the holes and one of the elongatealignment slots, the compression members selectively compressing themounts and the component together to fix them relative to one another.18. The attachment structure of claim 17 wherein the spaced slots areparallel to one another to enable movement of the component relative tothe mounts along the length of the slots.
 19. The attachment structureof claim 17 wherein the mating concave and convex surfaces are on a pairof washers corresponding to each mount residing between the bottom ofthe component and each mount.
 20. The attachment structure of claim 19wherein the compression member comprises a bolt including the shaft andhaving a head spaced from the component, the attachment structurefurther comprising a pair of washers having mating concave and convexsurfaces receiving the shaft of the bolt between the head of the boltand the component.